Inteins are unique protein insertion sequences capable of self-excision, enabling the covalent ligation of flanking extein peptides via amide bond formation. This process proceeds spontaneously without requiring external enzymes, cofactors, or chemical reagents, granting inteins exceptional biocompatibility and traceless performance in protein engineering applications. Split inteins represent a specialized and versatile subclass whose splicing domains are encoded by two separate gene fragments rather than a single continuous open reading frame. These fragments, known as the N-terminal (IntN) and C-terminal (IntC) split inteins, associate through non-covalent interactions including hydrophobic forces, hydrogen bonds, and van der Waals forces to assemble into an active three-dimensional structure, which then drives efficient extein ligation and enables protein trans-splicing. Protein trans-splicing mediated by split inteins has become a cornerstone for traceless protein ligation owing to its high specificity and irreversibility, fundamentally reshaping strategies for protein modification, assembly, and functional regulation. Compared with traditional chemical ligation methods, split intein systems require no complex chemical derivatization of peptide fragments and can operate efficiently at micromolar concentrations under physiological conditions, thus avoiding structural and functional damage caused by organic reagents. In contrast to enzymatic ligation tools such as sortase, split inteins eliminate the need for additional enzymes or cofactors, simplifying reaction systems, reducing costs, and minimizing non-specific side products. These distinctive advantages render split inteins highly promising for applications in chemical biology, synthetic biology, and biopharmaceutical development. In recent years, deepened mechanistic understanding has established structure-guided rational design as the primary approach to overcoming key limitations of split inteins, including intrinsic aggregation propensity, strict extein sequence dependence, and limited splicing efficiency. Bioinformatic tools have been used to identify aggregation-prone regions in the IntN fragment, and site-directed mutagenesis of hydrophobic residues, relocation of split sites, or removal of misfolding-prone sequences has substantially reduced in vitro aggregation and improved soluble expression and assembly activity. Rational engineering of catalytic residues and adjacent flexible loops has relaxed strict amino acid preferences at extein junctions, enhancing sequence tolerance and reducing the risk of functional impairment in target proteins. Consensus design based on multiple sequence alignments has yielded ultra-fast splicing variants such as Cfa DnaE and Cat-TerL, which exhibit significantly accelerated kinetics and improved tolerance to denaturing conditions. Meanwhile, advances in structural biology have further clarified the conformational dynamics and catalytic mechanisms of splicing, supporting the precise design of high-performance intein modules. On this basis, electrostatic interaction tuning and metagenomic screening have yielded multiple mutually orthogonal split intein pairs, enabling selective multi-fragment protein ligation and providing new routes for the efficient synthesis of large multi-domain functional proteins. With these engineered split inteins offering continuously improved performance and expanded applicability, protein trans-splicing has been widely applied in numerous cutting-edge areas of protein research and biomedicine. In gene delivery, split intein-based systems overcome the packaging limit of adeno-associated viral vectors, enabling the accurate reconstitution of large therapeutic proteins and base editors in target cells, thereby enhancing the efficacy and scope of gene therapy for genetic diseases. In internal protein sequence editing, split inteins mediate precise sequence replacement and modification in flexible regions or loops of target proteins, without the need for complex multi-step ligation and protein refolding involved in traditional protein semisynthesis. In protein-protein interaction studies, intein-mediated splicing covalently captures transient and weak intracellular complexes, enabling sensitive, high-throughput interaction detection and drug screening. In synthetic biology, conditionally controllable splicing systems support the construction of diverse intracellular and cell-surface biological logic gates for the precise regulation of cellular behavior. In mechanistic biochemical research, split inteins enable photocatalytic proximity labeling and site-specific tagging, allowing the preparation of homogeneous protein samples carrying precise post-translational modifications such as ubiquitination and polyglutamylation for chromatin interactome analysis and epigenetic studies. Moreover, covalent trapping strategies using split inteins stabilize transient enzymatic intermediates, providing unprecedented insights into molecular mechanisms such as nucleosome ubiquitination that are difficult to elucidate using conventional methods. This review systematically summarizes key technological advances in split inteins over the past decade, highlighting engineering strategies, mechanistic insights, and the development of orthogonal components. It comprehensively surveys emerging applications at the frontiers of protein research, analyzes current core challenges, and proposes future directions, particularly emphasizing artificial intelligence-driven de novo design and novel splicing pathways to break existing technical bottlenecks. By enabling traceless, efficient, and versatile protein manipulation, split inteins continue to serve as indispensable tools that drive innovation in protein engineering and fundamental life science research.

ObjectiveTranscranial magneto-acoustic stimulation (TMAS) is an emerging non-invasive neuromodulation technique that may provide a novel non-pharmacological intervention strategy for Parkinson's disease (PD). PD is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc), leading to motor impairments such as bradykinesia, tremor, and rigidity. Increasing evidence indicates that mitochondrial dysfunction and impaired mitochondrial quality control are central mechanisms underlying dopaminergic neuronal loss. In particular, abnormalities in mitophagy and mitochondrial fission-fusion balance contribute substantially to oxidative stress, energy metabolic failure, and neuronal injury. At present, most clinical treatments for PD mainly alleviate symptoms but do not effectively halt disease progression. Therefore, exploring new interventions targeting the core pathological mechanisms is of considerable significance. This study aims to investigate whether TMAS can improve neural damage and motor dysfunction in PD mice by regulating mitophagy and the fission/fusion dynamic balance, thereby providing theoretical and experimental support for its application in PD treatment. MethodsMale C57BL/6 mice were used in this study. A PD model was established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days. After model induction, mice in the intervention group received TMAS once daily for 14 consecutive days, whereas the corresponding control group received sham stimulation. The stimulation target was positioned over the primary motor cortex (M1). Motor performance was evaluated using the pole test and the open-field test. To verify the activation effect of TMAS on the target cortical region, c-Fos immunohistochemistry was performed in the M1. To assess nigral dopaminergic neuronal injury, tyrosine hydroxylase (TH) immunohistochemistry was used to quantify TH-positive neurons in the SNc. Mitochondrial function was evaluated by measuring reactive oxygen species (ROS) levels and adenosine triphosphate (ATP) content in the SNc. Western blot was further performed to determine the expression of mitophagy-related proteins, including PINK1, Parkin, LC3-II, and p62, as well as mitochondrial dynamics-related proteins, including Drp1 and Opa1. ResultsTMAS significantly increased the number of c-Fos-positive cells in M1 (P<0.000 1), indicating effective activation of neurons in the targeted cortical region. Compared with the control group, MPTP-treated mice exhibited marked motor dysfunction, including a significant reduction in total distance traveled in the open-field test (P<0.000 1) and mean speed (P=0.000 1), as well as significant prolongation of turn time and total climbing time in the pole test (P<0.000 1). These behavioral impairments were accompanied by a substantial loss of TH-positive dopaminergic neurons in the SNc, whereas TMAS significantly increased TH-positive neuron survival (P<0.000 1). In parallel, MPTP induced a pronounced increase in ROS levels and a significant reduction in ATP content, indicating severe mitochondrial dysfunction and energy metabolism impairment (P<0.01). TMAS treatment significantly improved motor performance, as reflected by the reversal of MPTP-induced impairment in the open-field and pole tests, and significantly reduced ROS accumulation (P<0.01) while restoring ATP production (P<0.001). At the molecular level, MPTP markedly downregulated PINK1 and Parkin, decreased p62 expression, increased LC3-II accumulation, elevated Drp1 expression, and reduced Opa1 expression, whereas TMAS significantly reversed these abnormalities, suggesting restoration of mitophagy-related mitochondrial quality control and re-establishment of mitochondrial fission-fusion balance. Collectively, these findings indicate that TMAS ameliorates MPTP-induced neurotoxicity and restores mitochondrial homeostasis and energy metabolism. ConclusionTMAS effectively attenuates neural damage and improves motor dysfunction in MPTP-induced PD mice. Its neuroprotective effects are closely associated with multidimensional regulation of the mitochondrial quality control system, including restoration of PINK1/Parkin-mediated mitophagy and rebalancing of Drp1/Opa1-related mitochondrial dynamics. Rather than acting only as a symptomatic neuromodulatory intervention, TMAS may influence a key pathological axis of PD by improving mitochondrial homeostasis in SNc and protecting nigral dopaminergic neurons. These findings provide experimental evidence supporting TMAS as a promising non-invasive physical intervention for PD.

BACKGROUND:Plate fixation is the mainstream method for the surgical treatment of distal femoral fractures.The intramedullary nailing has the advantages of minimally invasive,such as less soft tissue injury and bone blood supply destruction.At the same time,it is a central fixation and has better biomechanical effect.Therefore,retrograde intramedullary nailing has become another option for the internal fixation of distal femoral fractures.OBJECTIVE:The biomechanical characteristics of new retrograde intramedullary nail on lateral femur condyle,common femoral retrograde intramedullary nail,and lateral femur condyle anatomical locking plate for the treatment of A2-type distal femoral fractures were compared using finite element analysis,and the advantages of new retrograde intramedullary nail on lateral femur condyle was studied.METHODS:A new retrograde intramedullary nail on lateral femur condyle was designed,which was inserted into the bone cortex in front of the insertion point of the lateral collateral ligament of the lateral femoral condyle.A CT scan was performed on the lower limb bone of a male volunteer,and a three-dimensional model of the femur was established.The model was then segmented to create a three-dimensional model of a femoral distal A2-type fracture,The three-dimensional models of small(small group),standard type retrograde intramedullary nail on the lateral femoral condyle(standard group),common retrograde intramedullary needle(common group),and lateral femur condyle anatomical locking plate(plate group)were established respectively.The axial stresses of 600,1 800 N and the torsional load of 4 000,8 000 N·mm were applied to the models,and the displacement and stress of femur and the displacement,stress and shear force of internal fixators were observed in each group.RESULTS AND CONCLUSION:(1)When subjected to axial load of 600 and 1 800 N,the femoral peak displacement,the femoral peak stress,and the peak stress of interal fixation in the standard group were the lowest among the four groups.(2)When subjected to torsional load of 4 000 and 8 000 N·mm,the femoral peak displacement and peak displacement of the internal fixation in the standard group were the lowest among the four groups.(3)Compared with femoral lateral condylar locking plate and common retrograde intramedullary needle,the new retrograde intramedullary needle on lateral femur condyle has mechanical advantages of reducing stress concentration and decreasing the risk of internal fixation failure.

This paper introduces a real-world cohort research model for community-acquired pneumonia （CAP） based on the Jiangsu Traditional Chinese Medicine （TCM） Dominant Diseases Diagnosis and Treatment Data Platform. Firstly， data cleaning is performed by standardizing diagnosis， symptoms， treatment and imaging， intelligently extracting unstructured information， and cleaning and constructing a standardized database. Secondly， for cohort establishment， CAP patients across the province are screened in accordance with CAP diagnostic criteria to build a high-quality disease-specific cohort. Lastly， in terms of protocol design， the characteristics of TCM research and the CAP disease profile are considered to determine appropriate inclusion and exclusion criteria， estimate sample size， define interventions， outcomes and economic evaluations， providing a reference for real-world TCM research on CAP.

This paper introduces a real-world cohort research model for community-acquired pneumonia （CAP） based on the Jiangsu Traditional Chinese Medicine （TCM） Dominant Diseases Diagnosis and Treatment Data Platform. Firstly， data cleaning is performed by standardizing diagnosis， symptoms， treatment and imaging， intelligently extracting unstructured information， and cleaning and constructing a standardized database. Secondly， for cohort establishment， CAP patients across the province are screened in accordance with CAP diagnostic criteria to build a high-quality disease-specific cohort. Lastly， in terms of protocol design， the characteristics of TCM research and the CAP disease profile are considered to determine appropriate inclusion and exclusion criteria， estimate sample size， define interventions， outcomes and economic evaluations， providing a reference for real-world TCM research on CAP.

Objective: To analyze the associations of physical activity with overweight/obesity, depressive symptoms, and their co-occurrence among junior and senior high school students, so as to provide reference for optimizing physical activity intervention strategies and promoting healthy lifestyles. Methods: From March to November 2023, a cross sectional survey was conducted among 90 457 junior and senior high school students aged 11-18 years in Zhejiang Province using a stratified cluster random sampling method. Data on physical activity and dietary behavior were collected through questionnaires, height and weight were measured. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). The Chi-square test was used to examine differences, and Logistic regression was applied to evaluate the associations of physical activity characteristics with overweight/obesity, depressive symptoms, and their co-occurrence. Additionally, the effectiveness of physical activity performed on rest days versus work days was examined. Results: The prevalence of overweight/obesity, depressive symptoms, and their co-occurrence among junior and senior high school students were 25.1%, 27.9%, and 6.7%, respectively, with significant sex differences ( χ 2=2 005.3, 587.7, 99.6, all P <0.01). Logistic regression analysis showed that students with insufficient physical activity had a higher risk of overweight/obesity compared with those with sufficient physical activity ( OR=1.12, 95%CI=1.06-1.17, P <0.01). Comparing to students who exercised 0-1 day per week, those who exercised 5-7 days per week were associated with a reduced risk of overweight/obesity and depressive symptoms ( OR=0.93, 95%CI =0.90-0.97; OR=0.95, 95%CI =0.91-0.99, both P <0.05). When total activity volume and frequency were held constant, students with sufficient rest day physical activity had lower risks of overweight/obesity, depressive symptoms, and their co-occurrence than those with insufficient rest day activity (all P < 0.01). Conclusions Sufficient amount of physical activity and higher frequency of rest day physical activity are significantly associated with lower risks of overweight/obesity, depressive symptoms, and their co-occurrence in adolescents. Physical activity performed on rest days may confer greater health benefits than activity performed on work days.

This paper proposes a two-stage method integrating visual foundation models （VFM） and diffusion models. The segment anything model （SAM） as VFM is combined with the SegRefiner diffusion model to construct the SAM-SegRefiner framework for automated segmentation of edema， inflammation， and thrombus regions in histopathological images of hemorrhoidal tissue， providing a reproducible technical tool for the objective quantification of pathological morphology and its application in traditional Chinese medicine （TCM） syndrome research. Trained and validated on multi-center retrospective data， the SAM-SegRefiner model achieved an average pixel accuracy of 95.32% and a mean intersection over union （mIoU） of 66.81% on an independent test set， significantly outperfor-ming comparative models such as U-Net， MixU-Net， and SAM-Med2D， and also demonstrating robust cross-center generalization capability. Furthermore， by correlating the quantitatively segmented results from the model with the patients' TCM syndrome types， the potential associations between pathomorphological features and TCM syndrome differentiation have been explored. The analysis revealed no statistically significant differences in the degree of inflammatory infiltration and thrombus formation among different syndrome types， suggesting a complex relationship between local pathological changes and systemic syndrome manifestations.

ObjectiveThis study aimed to investigate whether Bushen Tongluo prescription inhibits macrophage polarization by regulating the Wnt3a/β-catenin signaling pathway， thereby reducing epithelial-mesenchymal transition and excessive extracellular matrix deposition， in order to elucidate the anti-pulmonary fibrosis mechanisms of Bushen Tongluo prescription and provide a new theoretical basis for the clinical treatment of pulmonary fibrosis. MethodsFifty male Sprague-Dawley （SD） rats were randomly divided into a blank group， model group， pirfenidone group， and high- and low-dose Bushen Tongluo prescription groups. Except for the blank group， the pulmonary fibrosis model was established by intratracheal instillation of bleomycin. Intervention was initiated on day 28 after modeling. The high- and low-dose Bushen Tongluo prescription groups were administered Bushen Tongluo prescription at doses of 30.88， 15.44 g·kg^-1， respectively， by intragastric gavage. The pirfenidone group was administered pirfenidone capsules at 110 mg·kg^-1 by intragastric gavage. The blank and model groups were given an equal volume of normal saline by gavage， once daily for 90 days. After treatment， the level of transforming growth factor-β₁ （TGF-β₁） in bronchoalveolar lavage fluid （BALF） was detected by enzyme-linked immunosorbent assay （ELISA）. Morphological changes in lung tissue and the collagen volume fraction were compared. The protein distribution and expression of E-cadherin， cytokeratin 19， α-smooth muscle actin （α-SMA）， vimentin， collagen type Ⅰ （Col Ⅰ）， and collagen type Ⅲ （Col Ⅲ） in lung tissue were detected by immunohistochemistry. The protein distribution and expression of CD68， arginase-1 （Arg-1）， inducible nitric oxide synthase （iNOS）， Wnt3a， and β-catenin in lung tissue were detected by immunofluorescence. The protein expression of Wnt3a and β-catenin in lung tissue was detected by Western blot， and the mRNA expression of Wnt3a and β-catenin was detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultsCompared with the blank group， a large number of inflammatory cells infiltrated the airway walls， alveolar spaces， and interstitial tissue in the model group， with obvious fibrous tissue hyperplasia. The level of TGF-β₁ in BALF was significantly increased. The protein expression of E-cadherin and cytokeratin 19 in lung tissue was decreased， whereas the protein expression of α-SMA， Vimentin， Wnt3a， β-catenin， Col Ⅰ， and Col Ⅲ was increased. The fluorescence-positive area ratios of CD68， Arg-1， iNOS， Wnt3a， and β-catenin in lung tissue were increased. The protein and mRNA expression levels of Wnt3a and β-catenin in lung tissue were significantly increased （P<0.01）. Compared with the model group， all treatment groups showed varying degrees of improvement in inflammatory cell infiltration and fibrous tissue hyperplasia in the airway walls， alveolar spaces， and interstitial tissue， decreased TGF-β₁ levels in BALF， increased protein expression of E-cadherin and cytokeratin 19 in lung tissue， decreased protein expression of α-SMA， Vimentin， Col Ⅰ， and Col Ⅲ， decreased fluorescence-positive area ratios of CD68， Arg-1， iNOS， Wnt3a， and β-catenin in lung tissue， and decreased protein and mRNA expression levels of Wnt3a and β-catenin in lung tissue （P<0.05， P<0.01）. ConclusionBushen Tongluo prescription can improve bleomycin-induced pulmonary fibrosis in rats by inhibiting epithelial-mesenchymal transition and reducing excessive extracellular matrix deposition. The mechanism may be related to inhibition of the Wnt3a/β-catenin signaling pathway and the macrophage polarization mediated by this pathway.

Objective To construct an index system for assessment of schistosomiasis transmission risk following natural disasters such as rainstorms, floods, earthquakes, mudslides, and landslides, so as to provide insights into rapid identification of schistosomiasis transmission risk post-disasters and formulation of targeted schistosomiasis control strategies. Methods An initial framework for the index system for assessment of schistosomiasis transmission risk following natural disasters was drafted through literature review, brainstorming, and focus group discussions. Two rounds of expert correspondence consultations were conducted using the Delphi method to refine and finalize the system, and the degrees of expert activeness, authority and endorse ment, and consensus were evaluated. In addition, the weights of each index were calculated using the analytic hierarchy process. Results A total of 18 experts participated in the consultation. The expert positive coefficients were 100.00% and 94.44% for two rounds of consultations, with authority coefficients of 0.92 and 0.94, respectively. The coefficients of coordination on the index importance, rationality and operability were 0.209, 0.185, 0.222 and 0.407, 0.214, 0.257 for two rounds of consultations, respectively, and all consistency tests were statistically significant (χ² = 246.771 to 505.278, all P values < 0.001). Following two rounds of expert consultations, an index system consisting of 6 first-level indicators, 15 second-level indicators, and 49 third-level indicators was ultimately constructed. In terms of first-level indicators, “disaster situation”, “previous epidemics”, “healthcare guarantee”, “response capacity” and “emergency recovery” had the highest weights, each at 18.18%. Regarding second-level indicators, “Schistosoma japonicum infections in animals”, “S. japonicum infections in snails” and “medical treatment” had the highest weights, each at 7.35%. In terms of third-level indicators, ten items had the highest weights, including “identification of schistosomiasis cases”, “detection of S. japonicum infections in wild feces”, “detection of S. japonicum infections in snails”, “reserves of schistosomiasis diagnostic/testing reagents and consumables”, “reserves of chemotherapy agents for human and animal schistosomiasis”, “reserves of cercariacides”, “periodical surveillance on schistosomiasis”, “identification of schistosomiasis transmission risk and timely response”, “normal provision of diagnosis and treatment services” and “post-disaster schistosomiasis surveillance”, each at 2.40%. Conclusion A scientific, systematic, and practical index system has been constructed for assessment of schistosomiasis transmission risk following natural disasters, which may provide insights into rapid post-disaster identification of schistosomiasis transmission risk, formulation of targeted schistosomiasis control strategies and optimization of resource allocation.

BACKGROUND:Plate fixation is the mainstream method for the surgical treatment of distal femoral fractures.The intramedullary nailing has the advantages of minimally invasive,such as less soft tissue injury and bone blood supply destruction.At the same time,it is a central fixation and has better biomechanical effect.Therefore,retrograde intramedullary nailing has become another option for the internal fixation of distal femoral fractures.OBJECTIVE:The biomechanical characteristics of new retrograde intramedullary nail on lateral femur condyle,common femoral retrograde intramedullary nail,and lateral femur condyle anatomical locking plate for the treatment of A2-type distal femoral fractures were compared using finite element analysis,and the advantages of new retrograde intramedullary nail on lateral femur condyle was studied.METHODS:A new retrograde intramedullary nail on lateral femur condyle was designed,which was inserted into the bone cortex in front of the insertion point of the lateral collateral ligament of the lateral femoral condyle.A CT scan was performed on the lower limb bone of a male volunteer,and a three-dimensional model of the femur was established.The model was then segmented to create a three-dimensional model of a femoral distal A2-type fracture,The three-dimensional models of small(small group),standard type retrograde intramedullary nail on the lateral femoral condyle(standard group),common retrograde intramedullary needle(common group),and lateral femur condyle anatomical locking plate(plate group)were established respectively.The axial stresses of 600,1 800 N and the torsional load of 4 000,8 000 N·mm were applied to the models,and the displacement and stress of femur and the displacement,stress and shear force of internal fixators were observed in each group.RESULTS AND CONCLUSION:(1)When subjected to axial load of 600 and 1 800 N,the femoral peak displacement,the femoral peak stress,and the peak stress of interal fixation in the standard group were the lowest among the four groups.(2)When subjected to torsional load of 4 000 and 8 000 N·mm,the femoral peak displacement and peak displacement of the internal fixation in the standard group were the lowest among the four groups.(3)Compared with femoral lateral condylar locking plate and common retrograde intramedullary needle,the new retrograde intramedullary needle on lateral femur condyle has mechanical advantages of reducing stress concentration and decreasing the risk of internal fixation failure.